1. Technical Field
The present invention relates to a liquid crystal device, an electro-optical panel light-emitting device and an electronic apparatus.
2. Related Art
A liquid crystal device utilized as a display unit of an electronic apparatus generally is equipped with a liquid crystal panel and a backlight that is an illuminator provided on a rear surface of the liquid crystal panel.
In such a liquid crystal device, LEDs (Light Emitting Diodes), for example, are used as the backlight, and a control circuit is provided for controlling the intensity of an illuminating light by regulating an amount of current supplied to the LEDs. In order to perform excellent display with a liquid crystal panel in the presence of an external light source of an electronic apparatus, there has been proposed a liquid crystal device (e.g., refer to JP-A-2005-121997) having a photo sensor constituted for example by a photo diode or photo transistor for measuring the intensity of an ambient light, and adjusting the intensity of backlight by means of a control circuit on the basis of an output of results obtained by the photo sensor.
As an existing method for measuring the intensity of ambient light by means of a photo sensor, there is a method of calculating light intensity by adopting a configuration in which a light-receiving surface of the photo sensor is irradiated with the ambient light for a predetermined period of time and then measuring a response time, which is the time taken from irradiation of the light-receiving surface with the ambient light to the output of an electronic signal produced by a photoelectric conversion. The above photo sensor has a characteristic that the response time thereof decreases as the intensity of the ambient light increases.
It is desirable that the photo sensor of such a liquid crystal device capable of adjusting the intensity of the illuminating light in accordance with the intensity of the ambient light has a higher resolution and an expanded detection range so as to enable the intensity of the illuminating light to be more finely adjusted. However, there is a problem that the resolution of the photo sensor of the above-mentioned existing liquid crystal device decreases as the intensity of the ambient light increases since the photo sensor has a characteristic that the response time thereof decreases as the intensity of the ambient light increases.